■ SCHEMATIC 4. The V_VAR power signal allows the user to
place any desired voltage on the target PIC plugged into socket
J8. We’ll use V_VAR to provide + 5 volts to the Explorer 8’s LCD
and LED components.

■ SCHEMATIC

3. Note that the
LED banks are
assembled on
differing I/O
ports. Jumpers

Let’s write some code to sequence the Explorer 8’s
banks of LED. This will be a walk in the park:

of J8 are labeled V_VAR (Voltage_Variable). V_VAR can be
driven by the + 5 volt voltage regulator we disabled; the
+ 3. 3 volt voltage regulator we disabled; or the variable
power supply circuit shown in Schematic 5. All we want to
do is make sure that the + 5 volt power rail supplied by our
D-Stick is routed to the Explorer 8’s + 5 volt main power
rail. This is easily done by jumpering pins 1 and 2 of J14.

Our jumper mission is complete. When we power-up
the new D-Stick, all of the Explorer 8’s + 5 volt power
indicator LEDs will illuminate.

The first order of business as it relates to programming
the Advanced D-Stick is to correctly set its configuration.
The good news is that the configuration words for it have
already been defined by the folks at ME Labs. You’ll find
the configuration code embedded within the D-Stick’s
application examples.